U.S. Pat. 4,253,713 issued Mar.3, 1981 and assigned to the common corporate assignee describes a fluid pressure assisted high-integrity rotating seal for sealing a shaft projecting through a housing bore and supported for shaft rotation within the bore by an anti-friction bearing. The assembly includes static and rotating seal races whose end faces abut. The patented rotary shaft seal meets requirements for specified dimensions and materials in a wide variety of industry applications and is readily applicable to environments in which gritty liquids, sewage, sludge, corrosive and abrasive can be prevented from reaching the bearings or mechanisms interior of the bearings. The patented rotary shaft seal is characterized by an annular bushing which rotates with the shaft, an annular static seal race, an annular neoprene boot, an annular rotating seal race, an annular carbon insert ring carried by the rotating seal race and an annular resilient seal sleeve. These various parts wear, requiring their replacement. The parts subjected to wear include the major bearing and seal housing components. Maintenance down time is relatively high and replacement of parts is achievable only with some difficulty.
It is therefore an object of the present to provide a improved rotary shaft seal in which the number of parts are minimized, a replaceable cartridge sleeve is provided which is specifically designed to bear the wear during shaft seal usage and which is easily and efficiently replaced to minimize maintenance down time of the apparatus housing the rotary shaft seal.
It is a further object of the present invention to provide such improved rotary shaft seal in which the replaceable wear sleeve cartridge cooperates with a labyrinth preseal bushing to provide a labyrinth preseal leading to the pressure assisted positive fluid seal defined by the annular static seal race, the annular rotating seal race, the replaceable wear sleeve cartridge and the labyrinth preseal bushing.